Here, a coastal promontory fort occupies a position where the sea itself does much of the work, with cliffs or steep drops cutting off three sides and leaving only the landward approach to be secured. That approach would typically have been sealed with a bank and ditch, sometimes stone-faced, transforming a natural feature into something deliberately fortified.

Promontory forts of this type are scattered along the Irish coastline, and Clare has a notable concentration of them. They are generally associated with the Iron Age, though some continued in use or were adapted well into the early medieval period. The form is simple but effective: choose a headland, cut it off from the mainland with one or more earthen or stone ramparts, and let the Atlantic do the rest. Who built the Ballard example, and when precisely, remains unclear from what has been recorded so far. The site belongs to a class of monument that is often easier to spot from the air or from a boat than from the land, where encroaching vegetation and coastal erosion can obscure the original lines of the defences.